1. Field of the Invention
The present invention relates to a method for interchanging contents information and a system for interchanging contents information. More particularly, the present intention relates to a method for interchanging contents information and a system for interchanging contents information, which are intended to reduce communication loads when contents information is interchanged at a high screen updating frequency, thereby saving power consumption.
2. Description of the Prior Art
With the recent wide spread of the broadband communication environment, a remarkable technical development has been made in the field of interchanging contents information, mainly that of image. In particular, the broadband wireless communication environment, which permits the application of portable telephones and portable remote terminals, is shaping up. In this environment, people can readily obtain a comparatively large amount of information by accessing the central database through a moving terminal. In this connection, a great development is expected in various sectors of business.
In related fields not limited to mobile communication, there have been proposed several techniques for receiving information from a remote terminal at an arbitrary position and providing the position-relating information through a communication line.
An example of them is a system to provide terrestrial photographic image information, as disclosed in Japanese Patent Laid-open No. 188800/2001. This system prepares a database in which map information corresponds to terrestrial photographic image information (which is a static image) and to provide this information through a communication network.
To be more specific, this system stores terrestrial photographic image information (such as photographs taken from satellites and airplanes) and advertisement information and provides specific pieces of such information meeting the geographic requirements according to the geographical information which has been sent from a terminal through a network. The system is constructed as shown in FIG. 73. It has a server system 7301, which consists of a database 7302 of terrestrial photographic image information (which stores and accumulates information of terrestrial photographic images taken from above and information of coordinate positions corresponding thereto) and a database 7303 of advertisement information (which stores correspondence between coordinate position information and advertisement information). On receipt of information 7304 (about position and specified requirements) from a user's terminal 7305 through a network 7307, the server system searches for the database 7302 of terrestrial photographic image information and the database 7303 of advertisement information in response to the received information. Then it transmits the corresponding terrestrial image and advertisement information 7306 to the user's terminal 7305 through the network 7307.
A new system has been disclosed in Japanese Patent Laid-open Nos. 66058/1998 and 193481/2000. This system consists of cameras (or any imaging devices) which have previously been arranged at prescribed positions, so that they take the actual scenes, and distributes the thus taken images in real-time through a communication network. The cameras in this system are so arranged that the user can specify any one of them and direct it to any direction be wants. Thus the system can provide the user in real-time with actual scenes (dynamic or static images) observed at a fixed point.
The system at the user's side is shown in FIG. 74. It consists of a GPS (Global Positioning System) receiver 7402, an advance direction input unit 7403 (which measures the direction in which the user is moving on foot or by vehicles or trains), a liquid crystal display 7404, and a control unit 7401 consisting of a personal computer to control the entire operation. To the control unit 7401 is on-line connected the actual scene image input device 7409 and the server 7408 for map database through the public telephone network 7407 for communications. The server 7408 for map database contains a Japan's nationwide map which is associated with identifying data such as coordinate data (longitude and latitude).
The actual scene image input device 7409 consists of a plurality of video cameras which are installed at various positions from which actual scenes are to be taken. It provides on-line a plurality of users, upon their request, with the actual scene images of the video cameras through the public telephone network 7407 for communications. The coordinate data of each actual scene point is previously set up, and the identifying data for these points are controlled by the map database server 7408.
Using the input device (keyboard 7405 or mouse 7406), the user instructs to display the actual scene which is viewed in his advancing direction. In compliance with this instruction, the control unit 7401 receives the user's present position and advancing direction (in terms of coordinate data and direction data) from the GPS receiver 7402 and the advancing direction input unit 7403. Then the control unit 7401 sends the coordinate data to the map database server 7408 through the public telephone network 7407 for communications, thereby inquiring the identifying data. On the basis of the thus acquired identifying data, the control unit 7401 specifies the actual scene image input device 7409 and its video camera and then accesses the actual scene image input device 7409 through the public telephone network 7407 for communications, thereby receiving on-line the actual scene, and displays it on the liquid crystal display 7404.
The above-mentioned system may also permit the user to specify any desired coordinate data (by using a pointing device, say, by clicking the mouse 7406) on a map instead of his present position. Thus the user can specify any one of the video cameras (constituting the actual scene image input device 7409) which is installed at the specified position and in the desired direction, and hence can view the actual scene as if the actual scene image input device 7409 performs fixed point observation.
Unfortunately, the conventional construction as mentioned above is designed for fixed point observation. In other words, it merely transmits and displays static mages (such as photographs and maps which do not change frequently from time to time). It can take dynamic images, but its position is fixed although its direction is variable. In other words, it can transmit dynamic images (contents information) only when the receiving side does not request to change the positions frequently. There is not frequent interactive information interchange.
Therefore, the above-mentioned system is suitable for transmission of limited contents information, but it lacks functions to transmit and display images very frequently. Such functions are required in the case where the user frequently demands the updating of position and viewing direction (and hence interactive information interchange). For example, the user moving at high speeds by car may want to know his present position continuously and also want the car navigator to display his present position with frequent updating.
In addition, the above-mentioned conventional system lacks provisions to relieve loads on communication networks and to save power consumption. Interactive information interchange necessarily increases loads, and the user's mobile unit needs batteries. It is necessary to eliminate waste communication and excess data for power saving.
Moreover, the above-mentioned conventional system is not suitable for storing or providing past images (say, 3 years ago or before 1945) or future images (say, 10 or 10,000 years later) which are of historical value, even though the images are taken at the fixed position and in the fixed direction, In addition, it is not designed to record images which change with time.
The present invention was completed in view of the foregoing. It is an object of the present invention to provide a method for interchanging contents information and a system for interchanging contents information. The method and system adequately provide contents information when there is a frequent demand for updating. They control the amount of communication, thereby reducing communication loads and communication tariff. They are suitable for preparing and storing contents information which changes with time.